Question

I have to choose a database for implementing a sharing system.

My system will have users and documents. I have to share a document with a few users.

---

Example:
There are 2 users, and there is one document.

So if I have to share that one document with both the users, I could do these possible solutions:

The current method I’m using is with MySQL (I don’t want to use this):

Relational Databases (MySQL)
    Users Table = user1, user2
    Docs Table = doc1
    Docs-User Relation Table = doc1, user1
                               doc1, user2

---

And I would like to use something like this:

NoSQL Document Stores (MongoDB)
    Users Documents:
        {
            _id: user1,
            docs_i_have_access_to: {doc1}
        }
        {
            _id: user2,
            docs_i_have_access_to: {doc1}
        }
    Document's Document:
        {
            _id: doc1
            members_of_this_doc: {user1, user2}
        }

---

And I don’t yet know how I would implement in a key-value store like Redis.

So I just wanted to know, would the MongoDB way I have given above, the best solution?
And is there any other way I could implement this? Maybe with another database solution?
Should I try to implement it with Redis or not?

Which database and which method should I choose and will be the best to share the data and why?

Note: I want something highly scalable and persistent. 😀

Thanks. 😀

Answer 1

Actually, you need to represent a many-to-many relationship. One user can have several documents. One document can be shared among several users.

See my previous answer to this question: how to have relations many to many in redis

With Redis, representing relationship with the set datatype is a pretty common pattern. You can expect to get better performance than with MongoDB for this kind of data model. And as a bonus, you can easily and efficiently find which users have a given list of documents in common, or which documents are shared by a given set of users.